An 82-year-old male farmer who came to our clinic in November 2004 had an abnormal mass shadow of soft tissue density in the left lower lobe on his chest radiography. He had once received sudden blunt chest trauma to his left anterior chest wall by heavy farm equipment and this had produced a relative large pulmonary laceration on the basal segment near aorta at age 47 in 1970. One month after the accident, he went to a local hospital for chest radiographic examination. Initially tuberculosis was suspected, but was denied after one year. In 1972 when he was 61-years-old, he had consulted our clinic on the first vivit, for evaluation the findings of the thin-walled parenchymal dead space with air-fluid level at the left basal segment which was confused with pleural effusion for a long time. Needle aspiration performed to the dead space yielded, whitish turbid fluid without tubercule bacillus was obtained. In November 2006, when he was 84-years-old, he again came to our clinic. By chest CT, the abnormal shadow was disclosed as a relatively large unilocular traumatic paneumatocele, 4×7 cm in size, with an air-fluid level, encircled by a thick wall with noticeable calcification, located in the basal segment of the entirely collapsed lower lobe. From the findings of leucocytes are still found in the fluid of the site of laceration, and both elevation of CRP and the blood sedimentation rate, persistent inflammatory reaction in the lacerated space was suspected. We report a rare case in which a traumatic pneumatocele existed for 36 years. This case suggests the importance of chest CT in the diagnostic procedure of traumatic pneumatocele.